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THE SLOW LORIS                                 545

deposit of fat formed chiefly at the root of the tail, and intended
to tide over the time of the creature's hibernation. But, as a
matter of fact, this peculiarity also exists in CMrogale. Of
Opolemur but two species are known, and of one of these, named
after Mr. Thomas of the British Museum, only three examples are
in existence in museums, that is to say in one museum—our own
at South Kensington. Many of these dwarf 31.em.urs are exceed-
ingly rare. In this genus and in the last two the palate has a pair
of posterior fenestrae, of which there are also traces in other Lemurs,
but which are particularly large in Microcebus. This is, of course,
a well-known character of the Marsupials, and also, which is more
important in the present connexion, of certain Insectivores.
Sub-Fain. 4. JLorisinae.—This sub-family is the only one with
a wide distribution, and it contains, with the exception of Tar&iits,
the only Asiatic members of the group. Correlated with its
wide distribution there is more divergence in anatomical characters
than is the case with the other sub-families of the Lemuridae.
In external features all the three genera of this sub-family agree
in their small size, their short or entirely deficient tail, large
staring eyes, and the rudimentary character, or absence, of the
index finger, which is never provided with a nail; in all of them
the thumb diverges widely from the other fingers, and the great
toe is so divergent as to be directed backwards. In the brain
there is one character common to all three genera, and that is
the small length of the angular fissitre. The caecum, which is
long, is supported by three folds, of which the median is anangious,
and is sometimes attached to the longer of tbe two lateral folds,
which are vascular. The members of this sub-family have more
dorsal vertebrae than are found in other Lemurs; the range is
from fourteen in Jboris, to sixteen in JWycticebiis.
The genus Nycticebv& contains only a single species, N. tardi-
gradus, though four other names have been given to supposed
varieties. Moreover, the genus itself has been named Stenops, as
also the next genus Xoris. The body of this animal is stouter than
that of the next to be described. Professor Mivart has pointed
out that, though Asiatic like the ILoris, it presents more resem-
blances to the African Potto. The index finger is small; the
inner of the two incisors is smaller than the outer, but both of
one side are close together. They may be reduced to one on each
side of tbe upper jaw.
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